JPS61273738A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the vapor deposition efficiency and productivity of the titled medium by forming a magnetic recording layer while irradiating either an X ray or a charged particle ray in the incident direction opened to an angle of >=45 deg. from the incident direction of the vapor flow wherein the maximum vapor depositing velocity is obtained by oblique vapor deposition. CONSTITUTION:A magnetic recording layer is formed while irradiating either an X ray or a charged particle ray in the direction opened to an angle of >=45 deg. from the incident direction of the vapor flow wherein the maximum vapor depositing velocity is obtained by oblique vapor deposition. The maximum vapor depositing velocity is obtained at the minimum incident angle of vapor on a polymeric film 8 as the substrate. At this time, an Ar ion beam is scanned in the width wise direction of the substrate, the angle theta is adjusted to >=45 deg. and the beam is regulated and irradiated on the part wherein the maximum vapor depositing velocity is obtained. The charged particle ray is irradiated so that the opening angle from the incident direction of the vapor flow wherein the maximum vapor depositing velocity is obtained in controlled to >=45 deg. and high coercive force Hc can be obtained even when the minimum incident angle is decreased. Consequently, the productivity is improved, the quality of the obtained magnetic recording layer is ameliorated and especially the still endurance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium, particularly a so-called metal thin film type magnetic recording medium in which a ferromagnetic metal thin film is disposed on a polymer film.

Conventional technology The conventionally popular magnetic recording media is a coated type in which a magnetic coating mainly consisting of acicular magnetic powder and a polymer binder is applied onto a polymer film and dried to form a magnetic recording layer. This is a magnetic recording medium.

On the other hand, metal thin film type films are made by forming ferromagnetic metals such as Go, Fe, and Ni or their alloys on polymer films using so-called physical paper deposition techniques such as vacuum evaporation, sputtering, or ion blasting. The magnetic recording medium has a high residual magnetic flux density because no non-magnetic binder is mixed in the magnetic recording layer, and as a result, the magnetic recording layer can be made thinner and loss can be reduced, resulting in high output. , and has excellent short wavelength response, and its practical application is strongly desired in magnetic recording, where the trend towards higher densities is increasing. However, in this type of thin film magnetic recording media, Co A sufficiently high coercive force (Ha) can be obtained by simply depositing magnetic metals and alloys on a polymer film, for example.
It is difficult to obtain a magnetic layer having .

In such thin film recording media, high coercive force (Ha
) The so-called oblique evaporation method, in which evaporated atoms are obliquely incident on the substrate, is well known as a method for obtaining a magnetic layer having Efforts are being made to consider materials, methods to increase the substrate temperature during vapor deposition, and combinations with underlying materials.

[For example, foreign journal: IEEE Transact
ionon Magnetics (IEE Magnetics Society Bulletin) Vow, MAG-20, g5, p,
[See p. a 18-820 (1984)] Problems to be Solved by the Invention However, the above-mentioned method has problems such as requiring the substrate to be heat resistant and being susceptible to rust. Since this method has not been found, there is a problem that it is insufficient for the mass production conditions of magnetic recording media.

Means for Solving the Problems In order to solve the above-mentioned problems, the method for manufacturing a magnetic recording medium of the present invention provides an Xls The magnetic recording layer is formed while being irradiated with either a charged particle beam or a charged particle beam.

Effect Even if the angle between the normal to the substrate and the vapor flow, which is required in the conventional oblique evaporation method, is not 45 degrees or more, the inside of the crystal may be damaged due to the influence of X-rays or charged particle beams. The arrangement of the elements that play a role in preventing domain wall movement, which increases the coercive force due to lattice defects, has anisotropy, and even at an incident angle of 46 degrees or less, the same coercive force (Ha ) is expected to be obtained.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the main parts of a vapor deposition apparatus used for carrying out the present invention. In Fig. 1, 1 is a cylindrical can, 2 is a delivery shaft, 3 is a winding shaft, 4 is an evaporation source container, 6 is a vapor deposition material, 6
is a vapor flow, 7 is a mask that limits the angle of incidence, 8 is a substrate, 9
10 is an ion source, 1o is an ion beam, 11 is a gas introduction boat, 12 is a variable leak valve, 13 is a vacuum pump, and 14 is a vacuum container.

In the figure, A indicates the maximum deposition rate in this case, and the constraint is that the angle θ shown here is 45 degrees or more in the present invention.

FIG. 2 is an enlarged cross-sectional view of a magnetic recording medium manufactured using the apparatus shown in FIG. In FIG. 2, 15 is a polymer film, 16 is a magnetic recording layer, and 17 is a protective film.

Vapor deposition material 6 is placed 33 cm directly below the cylindrical can 1 with a diameter of 1 m.
A Co--Ni alloy (Nt; 19 wt%) was placed as a material, and it was heated and evaporated with an electron beam (electron beam [maximum 2 oKV, 65 KW).

A prototype was produced under conditions such that the minimum incident angle of vapor with respect to the polymer film 8 serving as the substrate was the maximum vapor deposition rate.

At this time, the Ar 2 ion beam was scanned in the width direction of the substrate and adjusted so that θ was 45 degrees or more so that the portion where the maximum evaporation rate occurred was irradiated. The ion beam conditions are:
20KV, 3μA/d.

The surface temperature of the cylindrical can 1 was kept constant at 0°C.

Also, during vapor deposition, the inside of the vacuum container should be 3.6X 1
After evacuation to 0-'' Torr, oxygen was introduced from the outside and the pressure was maintained at 9 x 10' Torr for vapor deposition.

The thickness of the magnetic recording layer was constant at 0.1 μm. The relationship between the main conditions and RC is summarized in the table below. The polymer film used as the substrate was polyethylene terephthalate with a thickness of 1000 m.

In the table, the still durability time is the time until the main output decreases by 3 dB from the initial value in the still mode of the video tape recorder with an amorphous alloy head. This is a comparison when using a membrane to No. 35. 4. According to this example, as described above, by irradiating the charged particle beam so that the angle with respect to the incident direction of the vapor flow that provides the maximum deposition rate is 45 degrees or more,
Since high Ha can be obtained even if the minimum incident angle is made small, the vapor deposition efficiency can be improved, and the productivity can also be greatly improved as shown by the winding speed.

It can also be seen that it also has the effect of improving still durability as a magnetic recording medium.

Although an Ar ion beam was used in the embodiment, ion beams of He, Ne, Xe, N, O, etc., electron beams, and X-rays may also be used. Also,
As the magnetic recording layer, Co-Ni-00 is given as an example, but Co-0, Co-Or, Co-Mo
, Co-Ti, Co-W, Co-Ta,
Co-Ru, Co-Pt, etc. may also be used.

Furthermore, since Ha can be increased without raising the temperature, other polymer films with low heat resistance such as polypropylene, polycarbonate, and polyphenylene sulfide can also be used as the substrate.

Effects of the Invention As described above, according to the present invention, restrictions on the angle of incidence in oblique vapor deposition are relaxed, productivity can be improved, and the resulting magnetic recording layer is improved, particularly in still durability. 0

[Brief explanation of the drawing]

FIG. 1 is a block diagram of essential parts of a vapor deposition apparatus suitable for carrying out the present invention, and FIG. 2 is an enlarged sectional view of an example of a magnetic recording medium obtained by the method of the present invention. 1... Cylindrical can, 4... Evaporation source container, 5... Vapor deposition material, 6... Vapor flow, 7
...Mask, 8...Substrate, 9...
...Ion source, 10...Ion beam, 13.
...Vacuum pump, 14...Vacuum container.

Claims (1)

[Claims] The direction of incidence of the vapor flow that provides the maximum deposition rate in the oblique deposition method,
A method for manufacturing a magnetic recording medium, comprising forming a magnetic recording layer while irradiating either an X-ray or a charged particle beam in an incident direction that is open at an angle of 45 degrees or more.